This invention relates generally to sensors and more particularly to a sensor wherein the encoder is biased into close proximity to the sensing element.
Electronic control units (ECU) amass information from sensors and command the action of many vital functions of automobiles. The major areas in which ECUs have made substantial inroads are the engine, the transmission, the suspension and the anti lock brakes.
In all of these cases, the data describing the rotational motion or positional change are fed to the ECU, which prepares a calculated or mapped response ideal for the operational conditions. The ECU then initiates changes in the controlled function to minimize deviation from the ideal condition. High reliability, good resolution and economic costs are desired in sensor technology.
The need to sense the position of automobile steering columns or shafts has developed because of active suspension systems, electronic power steering assistance, safe driver warning systems, four wheel steering as well as anti-lock brake and traction control systems. As such, various sensors have been created to detect speed, direction and a reference pulse (i.e. true position). The conventional means for obtaining steering wheel angle information is an optical sensor system or accelerometer.
Some of the major improvements in passenger comfort have been achieved as a result of improving the ride characteristics of automobiles. The improvements have been accomplished by, among other things, the introduction of active and semi active suspension systems. Conventional systems sense lateral acceleration which is input into the ride control ECU. There are several ways of obtaining lateral acceleration data. One popular way is to use steering column rotational positional information in conjunction with the vehicle speed for determining the resulting lateral acceleration.
The above systems use encoders attached to a rotary shaft which are located in close proximity to the sensor. In situations where the shaft undergoes considerable vibrations or motion the encoder may be deflected away from the sensor, leading to unreliable sensor indications.
The foregoing illustrates limitations known to exist in present sensors. Thus, it is apparent that it would be advantageous to provide an alternative directed to overcoming one or more of the limitations set forth above. Accordingly, a suitable alternative is provided including features more fully disclosed hereinafter.